Manipulating energy migration within single lanthanide activator for switchable upconversion emissions towards bidirectional photoactivation

Abstract

Reliance on low tissue penetrating UV or visible light limits clinical applicability of phototherapy, necessitating use of deep tissue penetrating near-infrared (NIR) to visible light transducers like upconversion nanoparticles (UCNPs). While typical UCNPs produce multiple simultaneous emissions for unidirectional control of biological processes, programmable control requires orthogonal non-overlapping light emissions. These can be obtained through doping nanocrystals with multiple activator ions. However, this requires tedious synthesis and produces complicated multi-shell nanoparticles with a lack of control over emission profiles due to activator crosstalk. Herein, we explore cross-relaxation (CR), a non-radiative recombination pathway typically perceived as deleterious, to manipulate energy migration within the same lanthanide activator ion (Er3+) towards orthogonal red and green emissions, simply by adjusting excitation wavelength from 980 to 808 nm. These UCNPs allow programmable activation of two synergistic light-gated ion channels VChR1 and Jaws in the same cell to manipulate membrane polarization, demonstrated here for cardiac pacing.

Orthogonal Emissive Upconversion Nanoparticles: Material Design and Applications

“…Mei's group recently explored a nonradiative recombination pathway (cross-relaxation) to manipulate energy migration within the same lanthanide activator Er 3+ ions to achieve green and red emissions with the help of the adjustment of 808 and 980 nm excitation wavelength. [38] Typically, cross-relaxation was perceived as deleterious, but in their OUCNPs design in Figure 5h, the luminescence activator Er 3+ was incorporated into the core region, and Yb 3+ and Nd 3+ ions are two efficient Figure 5. TEM images following the growth progress of the dumbbell shaped OUCNPs: a) the core, b) core-shell and c) the dumbbell shaped nanoparticles.…”

“…Zhang's team describe the proposed control mechanism, the schematic shown in Figure 11b. [38] Incubated HEK293T cells with the OUCNPs, two light sensitive ion channels, Jaws and VChR1, are expressed. 980 nm light irradiation causes upconverted red emission and activation of Jaws resulting in Clinflux and membrane hyperpolarization, on the other side, 808 nm light irradiation causes upconverted green emission and activation of VChR1 resulting in an influx of cations such as Ca 2+ and Na + leading to membrane depolarization.…”

“…They aims to upgrade the UCNPs into OUCNPs including doping different UCNPs in separate layers, [26] multiple shell containing a layer of photon-inert shell to stop energy moving from one luminescent layer to another, [27,[33][34][35][36] controlling energy migration processes within single lanthanide activator, [37,38] and modularly assembled UCNPs. [30,39] Meanwhile, it is also easy for us to notice the appearance of OUCNPs in some new areas such as reversible photo-switching, [26][27][28][29] super-resolution imaging, [25] bidirectional photoactivation, [38] and programmable therapeutics, [30,32] and many other areas. A good understanding of what have been achieved in the area of OUCNPs over the last few years would help to make full use of the orthogonal upconversion phenomena and tap the potential of OUCNPs in more applied fields.…”

Intelligent Fe–Mn Layered Double Hydroxides Nanosheets Anchored with Upconversion Nanoparticles for Oxygen‐Elevated Synergetic Therapy and Bioimaging

“…[18,19] It is noteworthy that near-infrared (NIR) light (780-1400 nm) has deeper tissue penetration and lower tissue absorption than visible and ultraviolet light, has therefore been widely utilized in imaging technology. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] Coincidentally, rare-earth ions-based upconversion nanoparticles (UCNPs) are ideal candidates that can convert NIR photons into ultraviolet photons or visible light, thereby avoiding direct damage to tissues by ultraviolet light. [37][38][39][40][41][42][43][44][45][46][47][48][49] After loading a photosensitizer, deep tissue PDT can be realized.…”

Intracellular photoswitchable neuropharmacology driven by luminescence from upconverting nanoparticles

“…Subsequently, both spiropyran 19 and AB 20 photoswitches have been indirectly controlled using UCNP 21 . In parallel to these studies, biological photoswitches (light-gated ion channels [22][23][24][25][26][27][28][29] , and LOV domains 30 ) have been stimulated by the luminescence from UCNPs. Here we show that blue luminescence generated by 975 nm excitation of a NaYF 4 :TmYb nanoparticle can be used to stimulate cis to trans isomerization of the mono quaternary ammonium photoprobe AAQ.…”